Brief description of patient problem/setting

A 76-year-old male with PMHx of severe aortic stenosis, type 2 DM, asthma, is scheduled for transcatheter aortic valve replacement (TAVR). His PA meets with him before the procedure and mentions that the patient is of high surgical risk so TAVR, which is less invasive, would be safer than open heart valve replacement (SAVR). The patient states his younger brother, age 60s, also has severe aortic stenosis but is otherwise healthy. He wonders if his younger brother would also benefit from TAVR instead of SAVR if he is of low surgical risk.

 

Search Question: Is transcatheter AVR superior to surgical AVR regarding risks and benefits in low surgical risk patients?

 

PICO search terms:

P	I	C	O
Low surgical risk	Transcatheter aortic valve replacement	Surgical aortic valve replacement	mortality
Low operative risk	TAVR	SAVR	complications
Severe aortic stenosis	Transcatheter aortic valve implantation	Open heart valve replacement	Bleeding
	TAVI		arrythmias
	Percutaneous aortic valve replacement		survival

 

Search tools and strategy used:

Filters/limits use for all 3 search tools: last 5 years, age >18 y/o, MEDLINE, English, free full article/text

 

PubMed: (terms =TAVR AND SAVR AND low risk) + filters above  295 results

Cochrane: TAVR vs SAVR AND low risk +filters above  2 reviews and 166 trials

NEJM: TAVR AND low risk + some filters above + research filter  9 results

ScienceDirect: TAVR vs SAVR AND low risk + filters above + research + open access 170 results

 

How I narrowed my choices: Although I had specifically searched “low” risk on these databases, many results included articles with intermediate risk patients. I excluded those and only looked at articles that compared low surgical risk patients. Some studies only compared 1-2 outcomes between TAVR and SAVR (for example, paravalvular leak or new onset afib). I wanted to have studies that analyzed multiple outcomes between these two treatment options so that we could have a more encompassing view of the benefits and risks of the two procedures. Lastly, many studies that resulted from my search were cohort studies, so I narrowed my choices by favoring the systematic reviews and RCTs.

 

 

Articles Chosen:

1. “Transcatheter versus surgical aortic valve replacement in low-risk surgical patients: A meta-analysis of randomized clinical trial”

https://pubmed.ncbi.nlm.nih.gov/30638890/

Kheiri B, Osman M, Abubakar H, Subahi A, Chahine A, Ahmed S, Bachuwa G, Alkotob ML, Hassan M, Bhatt DL. Transcatheter versus surgical aortic valve replacement in low-risk surgical patients: A meta-analysis of randomized clinical trials. Cardiovasc Revasc Med. 2019 Oct;20(10):838-842. doi: 10.1016/j.carrev.2018.12.023. Epub 2019 Jan 4. PMID: 30638890.

 

PDF: 1pubmed

Type of study: Meta-analysis

Abstract

Background: Transcatheter aortic valve replacement (TAVR) is a valid option for patients with high or intermediate surgical risk. However, clinical outcomes of TAVR in low-risk patients are lacking. Our aim was to evaluate the efficacy and safety of TAVR versus surgical aortic valve replacement (SAVR) in low-surgical-risk patients.

Methods: Electronic database review was conducted for all randomized clinical trials (RCTs) that compared TAVR versus SAVR in low-risk patients. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) using a random-effects model.

Results: We included 3 RCTs totaling 604 patients (310 TAVR and 294 SAVR). Our results showed no significant difference in mortality between TAVR compared with SAVR (RR = 0.71; 95% CI = 0.22-2.30; P = 0.56), however, there was a significantly increased risk of pacemaker implantation (RR = 7.28; 95% CI = 3.94-13.42; P < 0.01) and moderate/severe paravalvular leakage (PVL) (RR = 6.74; 95% CI = 1.31-34.65; P = 0.02) with TAVR. Nevertheless, TAVR demonstrated a significantly reduced risk of post-procedural bleeding (RR = 0.40; 95% CI = 0.30-0.54; P < 0.01) and new-onset atrial fibrillation (RR = 0.36; 95% CI = 0.27-0.47; P < 0.01). Other clinical outcomes were not significantly different between the groups and included cardiovascular mortality, stroke, transient ischemic attack, and myocardial infarction.

Conclusions: Among low-risk patients, TAVR offered comparable efficacy outcomes and fewer bleeding events compared with SAVR. There were increased risks of pacemaker implantation and PVL associated with TAVR, though lower atrial fibrillation risks

 

  

2. “Transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis in people with low surgical risk”

https://www-cochranelibrary-com.york.ezproxy.cuny.edu/cdsr/doi/10.1002/14651858.CD013319.pub2/epdf/full

Kolkailah, A. A., Doukky, R., Pelletier, M. P., Volgman, A. S., Kaneko, T., & Nabhan, A. F. (2019). Transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis in people with low surgical risk. The Cochrane database of systematic reviews, 12(12), CD013319. https://doi.org/10.1002/14651858.CD013319.pub2

 

PDF: 2cochrane

Type of study: Systematic review

 

Abstract

Background: Severe aortic valve stenosis (AS) is a major cause of morbidity and mortality worldwide. The definitive management for severe AS is aortic valve replacement (AVR). The choice of transcatheter approach versus open‐heart surgery for AVR in people with severe AS and low surgical risk remains a matter of debate.

Objectives: To assess the benefits and harms of transcatheter aortic valve implantation (TAVI) compared to surgical aortic valve replacement (SAVR) in people with severe AS and low surgical risk.

Search methods: We searched the following databases for randomised controlled trials (RCTs) on 29 April 2019: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Web of Science Core Collection. We also searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform. We searched all databases from inception to present and imposed no restriction on language or date of publication.

Selection criteria: We included RCTs that compared TAVI and SAVR in adults (18 years of age or older) with severe AS and low surgical risk.

Data collection and analysis: We used the standard methodological procedures expected by Cochrane. Two authors independently screened titles and abstracts for inclusion, performed data extraction, and assessed risk of bias in the studies included. We analysed dichotomous data using the risk ratio (RR) and continuous data using the mean difference (MD), with respective 95% confidence intervals (CI). We assessed the certainty of evidence for each outcome using the GRADE approach. Our outcomes of interest were assessed in the short term (i.e. during hospitalisation and up to 30 days of follow‐up). Primary outcomes were all‐cause mortality, stroke, and rehospitalisation. Secondary outcomes were myocardial infarction (MI), cardiac death, length of hospital stay (LOS), permanent pacemaker (PPM) implantation, new‐onset atrial fibrillation, acute kidney injury (AKI), and any bleeding.

Main results: We identified four studies (13 reports), with 2818 participants, and one ongoing study. Overall certainty of evidence ranged from high to very low. There is probably little or no difference between TAVI and SAVR for the following short‐term outcomes: all‐cause mortality (RR 0.69, 95% CI 0.33 to 1.44; SAVR 11 deaths per 1000, TAVI 8 deaths per 1000 (95% CI 4 to 16); 2818 participants; 4 studies; moderate‐certainty evidence); stroke (RR 0.73, 95% CI 0.42 to 1.25; SAVR 21 strokes per 1000, TAVI 16 strokes per 1000 (95% CI 9 to 27); 2818 participants; 4 studies; moderate‐certainty evidence); MI (RR 0.82, 95% CI 0.42 to 1.58; SAVR 14 MI per 1000, TAVI 11 MI per 1000 (95% CI 6 to 21); 2748 participants; 3 studies; moderate‐certainty evidence); and cardiac death (RR 0.71, 95% CI 0.32 to 1.56; SAVR 10 cardiac deaths per 1000, TAVI 7 cardiac deaths per 1000 (95% CI 3 to 16); 2818 participants; 4 studies; moderate‐certainty evidence). TAVI may reduce the risk of short‐term rehospitalisation, although the confidence interval also includes the possibility of no difference in risk between groups (RR 0.64, 95% CI 0.39 to 1.06; SAVR 30 cases per 1000, TAVI 19 cases per 1000 (95% CI 12 to 32); 2468 participants; 2 studies; low‐certainty evidence). TAVI, compared with SAVR, probably increases the risk of PPM implantation (RR 3.65, 95% CI 1.50 to 8.87; SAVR 47 per 1000, TAVI 170 cases per 1000 (95% CI 70 to 413); number needed to treat for an additional harmful outcome (NNTH) = 7; 2683 participants; 3 studies; moderate‐certainty evidence). We are uncertain whether TAVI, compared with SAVR, affects the LOS in days, although it appears to be associated with shorter LOS. TAVI, compared with SAVR, reduces the risk of atrial fibrillation (RR 0.21, 95% CI 0.15 to 0.30; 2683 participants; 3 studies), AKI (RR 0.30, 95% CI 0.16 to 0.58; 2753 participants; 4 studies), and bleeding (RR 0.31, 95% CI 0.16 to 0.62; 2753 participants; 4 studies) (all high‐certainty evidence).

Authors’ conclusions: Our meta‐analysis indicates that, in the short term, TAVI probably has little or no mortality difference compared to SAVR for severe AS in individuals with low surgical risk. Similarly, there is probably little or no difference in risk of stroke, MI, and cardiac death between the two approaches. TAVI may reduce the risk of rehospitalisation, but we are uncertain about the effects on LOS. TAVI reduces the risk of atrial fibrillation, AKI, and bleeding. However, this benefit is offset by the increased risk of PPM implantation. Long‐term follow‐up data are needed to further assess and validate these outcomes, especially durability, in the low surgical risk population.

 

 

 

3. “Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients”

https://www-nejm-org.york.ezproxy.cuny.edu/doi/full/10.1056/NEJMoa1814052

Mack, M. J., Leon, M. B., Thourani, V. H., Makkar, R., Kodali, S. K., Russo, M., Kapadia, S. R., Malaisrie, S. C., Cohen, D. J., Pibarot, P., Leipsic, J., Hahn, R. T., Blanke, P., Williams, M. R., McCabe, J. M., Brown, D. L., Babaliaros, V., Goldman, S., Szeto, W. Y., … Smith, C. R. (2019). Transcatheter aortic-valve replacement with a balloon-expandable valve in low-risk patients. New England Journal of Medicine, 380(18), 1695–1705. https://doi.org/10.1056/nejmoa1814052.

 

PDF: 3NEJM

Type of study: Randomized control trial

 

Abstract:

BACKGROUND: Among patients with aortic stenosis who are at intermediate or high risk for death with surgery, major outcomes are similar with transcatheter aortic-valve replacement (TAVR) and surgical aortic-valve replacement. There is insufficient evidence regarding the comparison of the two procedures in patients who are at low risk.

METHODS: We randomly assigned patients with severe aortic stenosis and low surgical risk to undergo either TAVR with transfemoral placement of a balloon-expandable valve or surgery. The primary end point was a composite of death, stroke, or rehospitalization at 1 year. Both noninferiority testing (with a prespecified margin of 6 percentage points) and superiority testing were performed in the as-treated population.

RESULTS: At 71 centers, 1000 patients underwent randomization. The mean age of the patients was 73 years, and the mean Society of Thoracic Surgeons risk score was 1.9% (with scores ranging from 0 to 100% and higher scores indicating a greater risk of death within 30 days after the procedure). The Kaplan–Meier estimate of the rate of the primary composite end point at 1 year was significantly lower in the TAVR group than in the surgery group (8.5% vs. 15.1%; absolute difference, −6.6 percentage points; 95% confidence interval [CI], −10.8 to −2.5; P<0.001 for noninferiority; hazard ratio, 0.54; 95% CI, 0.37 to 0.79; P=0.001 for superiority). At 30 days, TAVR resulted in a lower rate of stroke than surgery (P=0.02) and in lower rates of death or stroke (P=0.01) and new-onset atrial fibrillation (P<0.001). TAVR also resulted in a shorter index hospitalization than surgery (P<0.001) and in a lower risk of a poor treatment outcome (death or a low Kansas City Cardiomyopathy Questionnaire score) at 30 days (P<0.001). There were no significant between-group differences in major vascular complications, new permanent pacemaker insertions, or moderate or severe paravalvular regurgitation.

CONCLUSIONS: Among patients with severe aortic stenosis who were at low surgical risk, the rate of the composite of death, stroke, or rehospitalization at 1 year was significantly lower with TAVR than with surgery.

 

 

4. “Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients”

https://www-sciencedirect-com.york.ezproxy.cuny.edu/science/article/pii/S0735109719361807

Kolte, D., Vlahakes, G. J., Palacios, I. F., Sakhuja, R., Passeri, J. J., Inglessis, I., &amp; Elmariah, S. (2019). Transcatheter versus surgical aortic valve replacement in low-risk patients. Journal of the American College of Cardiology, 74(12), 1532–1540. https://doi.org/10.1016/j.jacc.2019.06.076

 

PDF: Science Direct

Type of study: Meta-analysis

 

Abstract:

Background: Transcatheter aortic valve replacement (TAVR) has emerged as a safe and effective therapeutic option for patients with severe aortic stenosis (AS) who are at prohibitive, high, or intermediate risk for surgical aortic valve replacement (SAVR). However, in low-risk patients, SAVR remains the standard therapy in current clinical practice.

Objectives: This study sought to perform a meta-analysis of randomized controlled trials (RCTs) comparing TAVR versus SAVR in low-risk patients.

Methods: Electronic databases were searched from inception to March 20, 2019. RCTs comparing TAVR versus SAVR in low-risk patients (Society of Thoracic Surgeons Predicted Risk of Mortality [STS-PROM] score <4%) were included. Primary outcome was all-cause death at 1 year. Random-effects models were used to calculate pooled risk ratio (RR) and corresponding 95% confidence interval (CI).

Results: The meta-analysis included 4 RCTs that randomized 2,887 patients (1,497 to TAVR and 1,390 to SAVR). The mean age of patients was 75.4 years, and the mean STS-PROM score was 2.3%. Compared with SAVR, TAVR was associated with significantly lower risk of all-cause death (2.1% vs. 3.5%; RR: 0.61; 95% CI: 0.39 to 0.96; p = 0.03; I2 = 0%) and cardiovascular death (1.6% vs. 2.9%; RR: 0.55; 95% CI: 0.33 to 0.90; p = 0.02; I2 = 0%) at 1 year. Rates of new/worsening atrial fibrillation, life-threatening/disabling bleeding, and acute kidney injury stage 2/3 were lower, whereas those of permanent pacemaker implantation and moderate/severe paravalvular leak were higher after TAVR versus SAVR. There were no significant differences between TAVR versus SAVR for major vascular complications, endocarditis, aortic valve re-intervention, and New York Heart Association functional class ≥II.

Conclusions: In this meta-analysis of RCTs comparing TAVR versus SAVR in low-risk patients, TAVR was associated with significantly lower risk of all-cause death and cardiovascular death at 1 year. These findings suggest that TAVR may be the preferred option over SAVR in low-risk patients with severe AS who are candidates for bioprosthetic AVR.

 

 

Summary of the Evidence:

Author (Date)	Level of Evidence	Sample/Setting (# of subjects/ studies, cohort definition etc. )	Outcome(s) studied	Key Findings	Limitations and Biases
Kheiri B, Osman M, Abubakar H, Subahi A, Chahine A, Ahmed S, Bachuwa G, Alkotob ML, Hassan M, Bhatt DL (2019)	Meta-analysis	-3 RCTs -604 patients (310 TAVR and 294 SAVR) – inclusion criteria were: study must be a RCT, patients have low surgical risk	-Primary: all-cause mortality -Secondary: cardiovascular mortality, stroke, TIA, MI, PPM implantation, paravalvular leakage, post-procedural bleeding, post-procedural aifb	1. No significant difference between TAVR and SAVR regarding all-cause mortality, cardiovascular mortality, stroke, TIA, or MI. 2. TAVR had increased risk of pacemaker implantation and moderate/severe paravalvular leak TAVR had reduced risk of post-procedural bleeding and afib. 3. No significant difference in the type of TAVR bioprosthesis (self vs balloon expandable).	-Small # of trials, limited sample size, few events. -Patient cohort is older, so results have limited generalizability to younger population. -Lacked patient-level data, so could not assess the effect of transfemoral vs transthoracic access on the clinical outcomes of TAVR. -There was substantial heterogeneity in all-cause mortality and moderate-severe PVL (>20%). -Lacked long-term data for valve durability.
Ahmed A Kolkailah, Rami Doukky, Marc P Pelletier, Annabelle S Volgman, Tsuyoshi Kaneko, Ashraf F Nabhan (2019)	Systematic Review	-5 RCTs -2818 subjects, 18 years or older with severe aortic stenosis and low surgical risk -subjects were randomly assigned to either TAVR or surgical AVR	-Primary: all-cause mortality, stroke, rehospitalization -Secondary: MI, cardiac death, length of stay, permanent pacemaker implantation, new-onset afib, AKI, bleeding	1. TAVR vs SAVR has little-no difference in short term mortality, stroke MI, cardiac death. 2. TAVR may reduce risk of rehospitalization (but confidence interval was wide, so this is of low evidence). 3. TAVR reduces risk of afib, AKI, and bleeding. 4. TAVR increases risk of PPM implantation. 5. Further research is needed to validate these results and for long-term follow up data.	The review was conducted in accordance to a previously published protocol, “Kolkailah 2019,” with little deviation. -All studies chosen were at low risk of selection bias, but half were unclear in the allocation concealment methods – For potentially subjective outcomes, such as rehospitalization and LOS, the risk of detection bias as high – there was an overall imbalance between men and women, surgical approaches varied slightly, and valve types/generations were different across studies
Michael J. Mack, M.D., Martin B. Leon, M.D., Vinod H. Thourani, M.D., Raj Makkar, M.D., Susheel K. Kodali, M.D., Mark Russo, M.D., Samir R. Kapadia, M.D., S. Chris Malaisrie, M.D., David J. Cohen, M.D., Philippe Pibarot, D.V.M., Ph.D., Jonathon Leipsic, M.D., Rebecca T. Hahn, M.D., et al., for the PARTNER 3 Investigators (2019)	Randomized control trial	-950 patients enrolled, majority of them were from the US -severe aortic stenosis and low surgical risk -pts with increased risk of complications with either TAVR or open surgery were excluded -pts were randomly assigned to either TAVR (496) or surgical AVR (454)	-Primary: all-cause mortality at 1 year after the procedure. -Secondary: stroke, new- onset afib at 30 days, length of hospitalization, functional status, quality of life	1. At 30 days, TAVR had lower rate of stroke, new onset afib, and death than SAVR. 2. TAVR patients had shorter hospitalization. 3. At 1 year, the rate of death or disabling stroke was 1.0% in the TAVR group as compared with 2.9% in the surgery group. 4. In the TAVR group, 95.8% were able to be discharged to home or self-care compared to 73.1% in the SAVR group. 5. No significant difference in PPM placement or moderate-severe paravalvular leak in both groups at 30 days. 6. Mild paravalvular leak was higher in the TAVR group. 7. Life-threatening/major bleeding was 3.6% in the TAVR, and 24.5% in surgery. 8. TAVR patients had more rapid improvements in functionality and quality of life.	-Current results reflect only 1-year outcomes and do not address the problem of long-term structural valve deterioration -Adjudication of end points was not blinded, which could have resulted in bias in outcome assessment -The results apply only to the defined trial population, which excluded pts with poor transfemoral access, bicuspid aortic valves, or other factors that increased the risk of complications associated with either TAVR or surgery. -Findings cannot be extrapolated to TAVR performed with other systems or by less experienced operators -More pts in the surgery group than in the TAVR group withdrew from the trial -Missing data regarding NYHA class, 6-minute walk-test distance, KCCQ score, and follow-up echos were not fully accounted for.
Dhaval Kolte, MD, PHD, Gus J. Vlahakes, MD, Igor F. Palacios, MD, Rahul Sakhuja, MD, Jonathan J. Passeri, MD, Ignacio Inglessis, MD, Sammy Elmariah, MD, MPH (2019)	Meta-analysis	-4 RCTs that randomized 2,887 patients (1,497 to TAVR and 1,390 to SAVR). -Mean age of patients was 75.4 years old. -low risk patients only	Primary: death from any cause Secondary: cardiovascular death, stroke, MI, valve/heart failure rehospitalization, new/worsening afib, PPM implantation, major vascular complications, life-threatening/disabling bleeding, AKI, endocarditis, aortic valve reintervention, paravalvular leak, NYHA functional class >II. -All outcomes were assessed at 1 year follow up.	1. TAVR had significantly lower risk of all-cause death and cardiovascular death at 1 year. 2. TAVR had lower rates of new/worsening afib, severe bleeding, and AKI 3. TAVR had higher rates of PPM implantation and paravalvular leak 4. No significant different between TAVR and SAVR in major vascular complication, endocarditis, aortic valve re-intervention, and NYHA class>II.	-Did not have access to patient-level data so had to use study-level data -Only used 1-year outcome data -Event rates in one of the trials used estimated incidence instead of true observed incidence -Timing of events was not included, so had no time-to-event analyses -Small number of studies so meta-regression analysis could not be performed in order to determine if other variables (age, valve type, etc) had an effect on TAVR vs SAVR on outcomes.

 

 

Brief summary of conclusions:

Kheiri B, et al: In patients of low-surgical risk, TAVR was comparable in efficacy to SAVR and had fewer bleeding events and afib risks. TAVR had an increased risk of PPM implantation and paravalvular leakage.

Kolkailah et al: In the short term, little to no difference between TAVR and SAVR in risk of mortality, stroke, MI, and cardiac death. TAVR had reduced risk of rehospitalization, afib, AKI, and bleeding. TAVR had increased risk of PPM implantation. Long-term follow up data is needed.

Mack et al: Among patients with severe aortic stenosis who were at low surgical risk, the rate of the composite of death, stroke, or rehospitalization at 1 year was significantly lower with TAVR than with surgery. No significant difference in PPM placement or moderate-severe paravalvular leak in both groups at 30 days. SAVR had much higher risk of bleeding.

Kolte et al: TAVR was associated with significantly lower risk of all-cause death, cardiovascular death, new/worsening afib, severe bleeding, and AKI. TAVR had higher rates of PPM implantation and paravalvular leak.

 

Overarching conclusions: Many outcomes were analyzed in these studies, but overall there seemed to be no significant difference between TAVR and SAVR in mortality. Most studies noted an increased risk of PPM implantation in TAVR and increased risk of bleeding in SAVR. Other outcomes had inconsistent results and were discussed below in clinical bottom line section. All four of these articles only looked at short term outcomes, around 1 month to 1 year. More studies need to be done for analysis of long-term outcomes of SAVR vs TAVR.

 

 

Clinical Bottom Line:

Weight of evidence (in order from highest to lowest) and explanations:

1. Kolkailah et al (2019): a Cochrane systematic review, which is highly regarded. Had very little and minor limitations and biases in terms of the review conducted. It had a thorough analyses of the biases involved in the studies analyzed. It had the highest number of RCTs included, with a relatively large sample size of 2818.
2. Kolte et al (2019): A meta-analysis of 4 RCTs, with the largest sample size of 2887 patients. It analyzed a large number of important outcomes needed in order to provide the most information for my PICO question. Although the limitations noted were significant, they were not unique to this particular article and most could be said of the other articles chosen as well.
3. Kheiri et al (2019): A meta-analysis of only 3 RCTs with a smaller sample size of 604 patients. Inclusion criteria was appropriate for answering my PICO question but broad in comparison to the other studies. Limitations/biases were significant.
4. Mack et al (2019): the only RCT, which holds lower strength of evidence in comparison to the three above (meta-analyses/systematic reviews). This study had many limitations and biases as discussed in the table above. However, it was still a good article to choose as it had a large sample size with most patients from the US, meaning the results of the study could be applied to the US population.

 

Three out of the 4 articles had consistent results between one another in TAVR vs SAVR such as no significant difference in mortality, stroke, MI, and increased risk of PPM implantation (only 1 article claimed no significant difference between the two modalities in terms of PPM implantation). All 4 studies were consistent in noting that TAVR patients had reduced risk of post-procedural bleeding and afib. Although it seems TAVR overall had an increased risk of PPM implantation and paravalvular leak compared to surgical AVR, I believe these risks are not as serious as the increased risks that SAVR had (post-op bleeding, AKI, and afib). With this in mind, along with the improved functionality and quality of life in TAVR patients compared to open-heart, the clinical bottom line based on these findings would be that TAVR may have some superiority over SAVR, and TAVR is a good option for low-surgical risk patients. Given that a majority of results from all articles were based on 30 days or 1 year outcomes, studies regarding long term follow up should be done, perhaps comparing clinical and echocardiogram outcomes in 5-10 years after TAVR and SAVR. This data is needed to determine the long term functionality of these bioprosthetic valves, in order to provide more guidance on which method is best for low-surgical risk patients.